28,000 Cases of age related macular degeneration causing visual loss in people aged 75 years and above in the United Kingdom may be attributable to smoking

Recurrent choroidal neovascularization after macular translocation surgery with 360-degree peripheral retinectomy

PURPOSE

To evaluate the pattern of age-related macular degeneration in the new foveal location after macular translocation surgery with 360 degree peripheral retinectomy for neovascular age-related macular degeneration.

METHODS

Clinical data, fundus photos, and fluorescein angiograms of patients in the Duke Macular Translocation Study were reviewed with 2-year follow-up data.

RESULTS

With 56 patients completing follow-up, no patient developed de novo choroidal neovascularization (CNV), geographic atrophy, or drusen in the new subfoveal retinal pigment epithelium bed. By 2 years, 14 patients (25%) developed recurrent CNV and 13 of these 14 recurrences clearly arose from the old CNV bed. Of the 13 recurrences clearly arising from the old bed, 12 of them had recurrent CNV that involved the margin of the bed closest to the repositioned fovea. Smokers were 5.3 times (95% confidence interval: 1.2-24) more likely to develop recurrent CNV over 2 years. Despite treatment, median visual acuity for the 14 eyes with recurrent CNV was 20/200 compared with 20/80 in eyes without recurrence.

CONCLUSIONS

Findings in this study support the hypotheses that the development of CNV occurs via a signaling mechanism from the fovea.

Changes in retinal pigment epithelium related to cigarette smoke: possible relevance to smoking as a risk factor for age-related macular degeneration

Age-related Macular Degeneration (AMD) is a major cause of central vision loss in the elderly and smoking is a primary risk factor associated with the prevalence and incidence of AMD. To better understand the cellular and molecular bases for the association between smoking and AMD, we determined the effects of Benzo(a)Pyrene (B(a)P), a toxic element in cigarette smoke, on cultured retinal pigment epithelia (RPE) and we examined the RPE/choroid from mice exposed to chronic cigarette smoke. We measured: mitochondrial DNA (mtDNA) damage, phagocytic activity, lysosomal enzymes, exosome markers and selected complement pathway components. In the presence of a non-cytotoxic dose of B(a)P, there was extensive mtDNA damage but no nuclear DNA damage. RPE phagocytic activity was not altered but there were increased lysosomal activity, exocytotic activity and complement pathway components. Retinas from mice exposed to cigarette smoke contained markers for mtDNA damage, exosomes and complement pathway components surrounding Bruch's membrane. Markers for these processes are found in drusen from AMD patients. Thus, smoking may cause damage to mtDNA and increased degradative processes in the RPE. These altered cell biological processes in the RPE may contribute to the formation of drusen in individuals who are cigarette smokers and underlie susceptibility to genetic mutations associated with AMD.

Estimated prevalence and risk factor for age-related maculopathy

PURPOSE

To assess the estimate prevalence and risk factors for age-related maculopathy (ARM) in Seoul, Korea.

PATIENTS AND METHODS

We examined 9,530 subjects with, 40 years of age or older between January 2006 and December 2006 in Seoul, Korea. Subjects underwent fundus photography, clinical examinations (including blood analyses), and completed detailed questionnaires. Fundus images were graded according to definitions from the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

ARM was present in 235 subjects, corresponding to an estimate prevalence of 2.46%. Hepatitis B infection (positive status for HBsAg and HBcAb), serum triglyceride levels and high density lipoprotein levels remained as significant risk factors after age-adjustment. Multivariate analyses showed that the prevalence of ARM was significantly higher in older subjects [odds ratio (OR) 1.134; 95% CI 1.114-1.154] and those who were seropositive for hepatitis B surface antigen (OR 2.566; 95% CI 1.519-4.335).

CONCLUSION

The estimated prevalence of ARM was 2.46%. Age and hepatitis B infection may increase the risk of ARM.

Cost-effectiveness of smoking cessation to prevent age-related macular degeneration

Background

Tobacco smoking is a risk factor for age-related macular degeneration, but studies of ex-smokers suggest quitting can reduce the risk.

Methods

We fitted a function predicting the decline in risk of macular degeneration after quitting to data from 7 studies involving 1,488 patients. We assessed the cost-effectiveness of smoking cessation in terms of its impact on macular degeneration-related outcomes for 1,000 randomly selected U.S. smokers. We used a computer simulation model to predict the incidence of macular degeneration and blindness, the number of quality-adjusted life-years (QALYs), and direct costs (in 2004 U.S. dollars) until age 85 years. Cost-effectiveness ratios were based on the cost of the Massachusetts Tobacco Control Program. Costs and QALYs were discounted at 3% per year.

Results

If 1,000 smokers quit, our model predicted 48 fewer cases of macular degeneration, 12 fewer cases of blindness, and a gain of 1,600 QALYs. Macular degeneration-related costs would decrease by $2.5 million if the costs of caregivers for people with vision loss were included, or by $1.1 million if caregiver costs were excluded. At a cost of $1,400 per quitter, smoking cessation was cost-saving when caregiver costs were included, and cost about $200 per QALY gained when caregiver costs were excluded. Sensitivity analyses had a negligible impact. The cost per quitter would have to exceed $77,000 for the cost per QALY for smoking cessation to reach $50,000, a threshold above which interventions are sometimes viewed as not cost-effective.

Conclusion

Smoking cessation is unequivocally cost-effective in terms of its impact on age-related macular degeneration outcomes alone.

Smoking and the risk of age-related macular degeneration: a meta-analysis

PURPOSE

Some studies were undertaken to evaluate the association between cigarette smoking and age-related macular degeneration (AMD). This meta-analysis summarized the risk estimate of smoking and AMD and provided robust evidence for the association.

METHODS

Relevant studies were identified by searching PubMed and MEDLINE (from 1966 to June 2007) and reviewing the reference lists of key articles. The summary relative risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) were calculated. Study-specific risk estimates were pooled using a random-effects model.

RESULTS

Five prospective cohort and eight case-control studies met our inclusion criteria. Ever smoking was statistically significant associated with increased risk of AMD among cohort studies (RR, 1.61; 95% CI, 1.01-2.57) or case-control studies (RR, 1.76; 95% CI, 1.56-1.99). Current smokers were at higher risk of AMD than past smokers. Both geographic atrophy (GA) and neovascular AMD (NV) are subtypes of AMD. A significant relationship was found between smoking and GA risk. Smoking increased the risk of NV, with marginal nonsignificance (RR, 1.47; 95% CI, 0.92-2.37) in cohort studies and significance in case-control studies (RR, 1.96; 95% CI, 1.69-2.27).

CONCLUSIONS

This meta-analysis indicated smoking, especially current smoking, was significantly associated with increased risks of AMD and its subtypes.

Prevalence of retinal diseases and their pattern in Tehran: the Tehran eye study

PURPOSE

To determine the prevalence of retinal diseases and their pattern in Tehran through a population-based study.

METHODS

In 2002, through a stratified random cluster sampling, 6497 citizens representing a cross-section of the population of Tehran were selected from 160 clusters. Eligible people were recruited through a door-to-door household survey in selected clusters and transferred to a clinic for an extensive eye examination and interview.

RESULTS

The prevalence of retinal diseases was 8.56 per 100 (95% CI, 7.74-9.39). Acquired retinopathies (3.33 per 100) and peripheral retinal lesions (3.29 per 100) were the most common retinal diseases in our population. Cataract (12.47 per 100) was the major ocular comorbidity; high blood pressure (21.14 per 100) and diabetes mellitus (15.99 per 100) were the main systemic comorbidities among 415 patients with retinal diseases. The prevalence of low vision on the basis of best-corrected and presenting visual acuity was 0.63 and 2.87 per 100 in 415 patients with retinal disease. Two patients (0.48 per 100) were blind with corrected and presenting visual acuity. The prevalence of diabetic retinopathy in the studied population was 0.61 per 100 (95% CI, 0.39-0.82) and age-related macular degeneration was detected in 1.95 per 100 (95% CI, 1.55-2.34) of the population.

CONCLUSIONS

These findings reveal a considerable prevalence of retinal diseases in the population. The prevalence might be underestimated due to the lack of fundus photography. The findings could be considered for case finding and planning treatment programs for specific retinal diseases.

[Lutein and antioxidants in the prevention of age-related macular degeneration]

Demographic developments in Europe and North America are causing an increase of age-related diseases. Age-related macular degeneration (AMD) is one of the leading causes of severe central visual acuity loss in elderly people and seems to be an economic problem, too. There is evidence that oxidative damage is an important factor for exacerbation of AMD. Macular pigment with its antioxidative effect may serve as"natural sunglasses" filtering the blue light acting as a possible source of photooxidative damage to the neurosensory retina. The macular pigment consists mostly of lutein and zeaxanthin. These micronutrients from the group of carotenoids, as is the case for vitamins (vitamins C, E, and beta-carotene), cannot be synthesized in mammals and that is the reason why the role of micronutrition or its supplementation and its correlation to AMD progression has been discussed for years. The results of currently published studies are often contradictory. At present there are no results from randomized controlled studies confirming that supplementation of lutein and zeaxanthin can reduce the risk for AMD. Several epidemiological studies investigating the impact of antioxidants and omega-3 fatty acids on the incidence of AMD provided conflicting results.Up to now, AREDS is the largest randomized controlled study investigating the effect of supplementation of antioxidants, zinc, and copper on the progression of AMD. AREDS showed a significant effect of this supplementation in some particular groups of patients with AMD. The supplementation of lutein and omega-3 fatty acids is not toxic but a positive effect has not been proven by randomized studies.

Independent Effects of Complement Factor H Y402H Polymorphism and Cigarette Smoking on Risk of Age-Related Macular Degeneration

OBJECTIVE

To examine the potential gene-environment interaction between cigarette smoking and the complement factor H (CFH) T1277C polymorphism, 2 strong risk factors for age-related macular degeneration (AMD).

DESIGN

Retrospective case-control study.

PARTICIPANTS

A university clinic-based sample of 599 people with AMD and 242 controls.

METHODS

Standard criteria were used to rate disease severity (grades 1-5) from fundus photographs. Individuals were classified as "ever smokers" or "never smokers" based on self-reported lifetime smoking of at least 100 cigarettes. Intensity of smoking was evaluated by calculating pack-years of smoking, which was analyzed as a continuous variable, and by categorizing individuals as smoking more or less than the median 30 pack-years. T1277C genotypes were determined by sequencing the polymorphic site. Generalized estimating equations were used to analyze the effects of smoking and genotype, controlling for age and gender and adjusting for correlations among related subjects.

MAIN OUTCOME MEASURE

Age-related macular degeneration affection status.

RESULTS

Interaction terms between T1277C genotype and smoking variables were not statistically significant, indicating a multiplicative relationship between risk factors. Effects of both T1277C genotype and cigarette smoking were stronger when comparing neovascular (grade 5) AMD with grade 1 controls than when comparing all cases (grades 3-5) with grades 1 to 2 controls.

CONCLUSION

These results suggest that cigarette smoking and T1277C are independent risk factors for AMD and that both risk factors are associated more strongly with neovascular AMD than all forms of AMD combined.

‘Smoke gets in your eyes’: a research-informed professional education and advocacy programme

Smoking is associated with common sight-threatening eye conditions. We suspected that this link was little known and it might be a potent novel health promotional tool. We therefore developed a programme ultimately aiming to reduce the burden of eye disease attributable to smoking. The programme aims were to (1) raise awareness of the link between smoking and eye disease and advocate changes in relevant policies and (2) investigate and promote change in professional practice so that smokers are identified and routinely offered smoking cessation advice/support in eyecare settings. An inter-professional team developed a programme of research and education targeting policy-makers, healthcare professionals, the public and patients. We reviewed evidence about the causal link between smoking and eye disease, researched current awareness of the link, researched current practice of eyecare health professionals, produced health education materials and campaigned for policy changes. The series of projects was completed successfully, achieving media coverage, confirming the causal link between smoking and eye disease and demonstrating low awareness of this association. Healthcare leaders and policy-makers were engaged in our programme resulting in commitment, in principle, from the UK's Chief Medical Officer and the European Commission to consider including warning labels related to blindness on cigarette packets.

Acute effects of cigarette smoking on multifocal electroretinogram

BACKGROUND

Cigarette smoking was shown to have stimulant effects on pattern visual-evoked potentials. The aim of this study was to investigate the acute effects of cigarette smoking on multifocal electroretinogram (mfERG).

METHODS

This prospective case-control study was held in a tertiary referral centre in Turkish Armed Forces. mfERGs were investigated in a group of habitual smokers (30 right eyes of 30 subjects) in separate real smoking and sham smoking sessions. mfERG responses of the subjects were recorded after overnight abstinence. The responses were averaged over five retinal regions, the central hexagon (CH; central 6 degrees) and four concentric rings (ring 1 [R1; 7-12 degrees], ring 2 [R2; 13-18 degrees], ring 3 [R3; 19-24 degrees], ring 4 [R4; 25-30 degrees]). On each session mfERGs were recorded before (BS) and after smoking (AS) conditions.

RESULTS

Regarding P1 amplitudes (first positive deflection of the mfERG) in the real smoking sessions, the differences were significant in the CH (BS: 66.2 +/- 16.3 microV, AS: 73.3 +/- 19.6 microV, P < 0.001), in R1 (BS: 44.3 +/- 13.0, AS: 48.3 +/- 16.0, P = 0.004) and in R2 (BS: 30.1 +/- 8.3, AS: 33.7 +/- 9.7, P = 0.002). Similar results were found for N1 amplitudes and P1 and N1 (first negative deflection of the mfERG) latencies in the CH, R1 and R2. The differences in outer retinal areas (R3, R4) in the real smoking sessions and in all rings in the sham smoking sessions were not significant.

CONCLUSION

Cigarette smoking may stimulate the central retinal areas in the acute phase. This effect may be related with the stimulant effect of nicotine on neurotransmission, deleterious effects on retinal and/or choroidal circulation, carbon monoxide toxicity and nicotine withdrawal.

The LOC387715 polymorphism and age-related macular degeneration: replication in three case-control samples

PURPOSE

Age-related macular degeneration (AMD) is a multifactorial blinding disease in the elderly. LOC387715 harbors a single-nucleotide polymorphism that has an association with AMD. This study was conducted to confirm the association between LOC387715 and AMD and to refine estimates of the impact of this gene variation in using samples from three studies: an Australian population-based study and two U.S. clinic-based case-control studies.

METHODS

Cases and controls were collected from a National Eye Institute (NEI) clinical protocol (n = 240), the Age-Related Eye Disease Study (AREDS; n = 488), and the Blue Mountains Eye Study (BMES; n = 851). After DNA extraction, subjects were genotyped for the LOC387715 Ala69Ser polymorphism (rs10490924).

RESULTS

The combined NEI and AREDS samples yielded odds ratios (ORs) of 2.61 (95% CI 1.89-3.61, P = 1.42 x 10(-9)) and 8.59 (95% CI 4.49-16.5, P = 3.56 x 10(-13)) for the heterozygous and homozygous risk alleles, respectively. The corresponding odds ratios in the BMES sample were 1.69 (95% CI: 1.25-2.28, P = 0.0007) and 2.20 (95% CI: 1.05-4.62, P = 0.038) for the heterozygous and homozygous groups. Neither set of samples showed statistically significant interaction with smoking, although there appeared to be a trend of interaction between smoking and LOC387715 for risk of advanced AMD.

CONCLUSIONS

Although these data from three case-control samples support an AMD genetic risk marker harbored within LOC387715, the nested case-control data from the population-based BMES samples showed lower estimates than from the clinic-based samples. This may be because the BMES samples consisted of largely early AMD cases while the clinic-based AMD samples consisted exclusively of advanced cases.

Cigarette smoking and age-related macular degeneration in the EUREYE Study

OBJECTIVE

To examine the association between cigarette smoking and age-related maculopathy (ARM) including age-related macular degeneration (AMD) in the European population.

DESIGN

Cross-sectional study.

PARTICIPANTS

Four thousand seven hundred fifty randomly sampled > or =65-year-olds from 7 study centers across Europe (Norway, Estonia, United Kingdom, France, Italy, Greece, and Spain).

METHODS

Participants underwent an eye examination and digital retinal photography. The images were graded at a single center. Smoking history was ascertained by a structured questionnaire administered by trained fieldworkers. Multinomial and binary logistic regressions were used to examine the association between smoking history and ARM grade and type of AMD, taking account of potential confounders and the multicenter study design.

MAIN OUTCOME MEASURES

Photographic images were graded according to the International Classification System for ARM and stratified using the Rotterdam staging system into 5 exclusive stages (ARM 0-3 and ARM 4, also known as AMD). Age-related macular degeneration also was classified as neovascular AMD or geographic atrophy (GA).

RESULTS

One hundred fifty-eight cases were categorized as AMD (109 neovascular AMD and 49 GA); 2260 had no signs of ARM (ARM 0). Current smokers had increased odds of neovascular AMD (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.4-4.8) or GA (OR, 4.8; 95% CI, 2.1-11.1), whereas for ex-smokers the odds were around 1.7. Compared with people with unilateral AMD, those with bilateral AMD were more likely to have a history of heavy smoking in the previous 25 years (OR, 5.1; 95% CI, 1.3-20.0). The attributable fraction for AMD due to smoking was 27% (95% CI, 19%-33%). There was no consistent association with ARM grades 1 to 3 and smoking.

CONCLUSIONS

These findings highlight the need for increasing public awareness of the risks associated with smoking and the benefit of quitting smoking. Patients with unilateral disease who are current smokers should be advised of the risk of second-eye disease.

Acrolein, a toxicant in cigarette smoke, causes oxidative damage and mitochondrial dysfunction in RPE cells: protection by (R)-alpha-lipoic acid

PURPOSE

To understand better the cell and molecular basis for the epidemiologic association between cigarette smoke, oxidant injury, and age-associated macular degeneration, the authors examined the effects of acrolein, a major toxicant in cigarette smoke, on oxidative mitochondrial damage in retinal pigment epithelial (RPE) cells and the reduction of this damage by lipoic acid.

METHODS

Cultured human ARPE19 cells and primary cultures of human fetal (hf)RPE were treated with acrolein. The toxicity of acrolein and the protective effects of R-alpha-lipoic acid were examined with a variety of previously described techniques.

RESULTS

Acute acrolein exposure exceeding 50 microM (24 hours) in ARPR19 cells caused toxicity, including decreases in cell viability, mitochondrial potential, GSH, antioxidant capacity, Nrf2 expression, enzyme activity (mitochondrial complexes I, II, III; superoxide dismutase; and glutathione peroxidase). Acute exposure also increased oxidant levels, protein carbonyls, and calcium. Continuous acrolein exposure over 8 or 32 days caused similar toxicity but from 10- to 100-fold lower doses (0.1-5 microM). Pretreatment with R-alpha-lipoic acid effectively protected ARPE-19 cells from acrolein toxicity. Primary hfRPE cells were comparable to the ARPE-19 cells in sensitivity to acrolein toxicity and lipoic acid protection.

CONCLUSIONS

These results show that acrolein is a mitochondrial toxicant in RPE cells and that acrolein-induced oxidative mitochondrial dysfunction is reduced by lipoic acid. The similar sensitivity of the ARPE-19 and hfRPE cells suggests that both models are useful for studying RPE toxicity and protection. These experiments indicate that mitochondria-targeted antioxidants such as lipoic acid may be an effective strategy for reducing or preventing chronic oxidant-induced RPE degeneration in vivo from a variety of sources, including cigarette smoke.

Acute effects of cigarette smoking on pattern electroretinogram

In this study, acute effects of cigarette smoking on the pattern electroretinogram (PERG) were investigated. First, variability of the PERG was studied in a group of young male smokers (26 right eyes of 26 subjects). Then PERGs were investigated in a group of habitual smokers (17 right eyes of 17 subjects) in separate real smoking and sham smoking sessions. On each session PERGs were recorded pre-smoking (PS), immediately after smoking (IAS) and 5 min after smoking (5th) conditions. Real smoking significantly increased P50 amplitudes and decreased N95 latencies. Regarding P50 amplitudes in the real smoking sessions, the differences were significant between PS and IAS (PS: 3.3 +/- 0.5 muV, IAS: 3.7 +/- 0.7microV, P = 0.015) and between PS-5th (PS: 3.3 +/- 0.5microV, 5th: 4.1 +/- 0.9microV, P = 0.039). There was significant difference (P = 0.024) between N95 latencies of PS (98.5 +/- 6.9 ms) and IAS (94.7 +/- 5.1 ms) in the real smoking sessions. No statistically significant difference was observed in sham smoking sessions. Our results indicated, for the first time, that cigarette smoking may influence PERG amplitude and latency significantly in habitual smokers.

Risk factors for photodynamic therapy of predominantly classic choroidal neovascularization in age-related macular degeneration

PURPOSE

To investigate the influence of various risk factors for age-related macular degeneration (AMD) on the rate of undergoing photodynamic therapy (PDT).

DESIGN

An observational population based cohort study.

METHODS

SETTINGS

A district of the largest health maintenance organization (HMO) in Israel.

STUDY POPULATION

All HMO members in the district, older than 50 years on January 1, 2001, who did not terminate their membership until May 31, 2005 (139,894 members); of those, 283 underwent PDT for AMD during the study period (775 procedures).

OBSERVATION PROCEDURES

We extracted information from the chronic disease registry of the HMO as well as demographic information including age, gender, country of birth, place of residency, and social security economic status.

MAIN OUTCOME MEASURES

Effect of various risk factors for AMD on the rate of PDT.

RESULTS

The age-adjusted proportion of patients requiring PDT was significantly higher in hypertensives (P = .03, chi2 test), in hyperlipidemics (P = .002), in ischemic heart disease patients (P = .002) and among males (P = .03) and Ashkenazi Jews (P = .02). No significant difference in PDT rates was noted in diabetics, congestive heart failure (CHF), and chronic renal failure (CRF) patients. PDT rates were lower in the lower socioeconomic class (P = .002). Logistic regression found a significant effect of age, hyperlipidemia, hypertension, socioeconomic status, and gender on the rate of PDT, while ischemic heart disease (IHD), diabetes, CHF, CRF, place of birth, and place of residence did not contribute significantly to the model.

CONCLUSIONS

Advanced age, hypertension, hyperlipidemia, male gender, and socioeconomic status are risk factors for undergoing PDT for predominantly classic neovascular AMD.

Synergic effect of polymorphisms in ERCC6 5' flanking region and complement factor H on age-related macular degeneration predisposition

This study investigates age-related macular degeneration (AMD) genetic risk factors through identification of a functional single-nucleotide polymorphism (SNP) and its disease association. We chose ERCC6 because of its roles in the aging process, DNA repair, and ocular degeneration from the gene disruption. Bioinformatics indicated a putative binding-element alteration on the sequence containing C-6530>G SNP in the 5' flanking region of ERCC6 from Sp1 on the C allele to SP1, GATA-1, and OCT-1 on the G allele. Electrophoretic mobility shift assays displayed distinctive C and G allele-binding patterns to nuclear proteins. Luciferase expression was higher in the vector construct containing the G allele than that containing the C allele. A cohort of 460 advanced AMD cases and 269 age-matched controls was examined along with pathologically diagnosed 57 AMD and 18 age-matched non-AMD archived cases. ERCC6 C-6530>G was associated with AMD susceptibility, both independently and through interaction with an SNP (rs380390) in the complement factor H (CFH) intron reported to be highly associated with AMD. A disease odds ratio of 23 was conferred by homozygozity for risk alleles at both ERCC6 and CFH compared with homozygozity for nonrisk alleles. Enhanced ERCC6 expression was observed in lymphocytes from healthy donors bearing ERCC6 C-6530>G alleles. Intense immunostaining of ERCC6 was also found in AMD eyes from ERCC6 C-6530>G carriers. The strong AMD predisposition conferred by the ERCC6 and CFH SNPs may result from biological epistasis, because ERCC6 functions in universal transcription as a component of RNA pol I transcription complex.

Does smoking influence the type of age related macular degeneration causing visual impairment?

AIMS

To assess the influence of smoking on the type of age related macular degeneration (AMD) lesion causing visual impairment in a large cohort of patients with AMD at a tertiary referral UK centre.

METHODS

Prospective, observational, cross sectional study to analyse smoking data on 711 subjects, of western European origin, in relation to the type of AMD lesion present. Colour fundus photographs were graded according to a modified version of the international classification. Multiple logistic regression analysis was performed, adjusting for age and sex using the statistical package SPSS ver 9.0 for Windows. chi(2) tests were also used to assess pack year and ex-smoker data.

RESULTS

578 subjects were graded with neovascular AMD and 133 with non-neovascular AMD. There was no statistically significant association found between smoking status or increasing number of pack years and type of AMD lesion. The odds of "current smokers" compared to "non-smokers" developing neovascular rather than non-neovascular AMD when adjusted for age and sex was 1.88 (95% CI: 0.91 to 3.89; p = 0.09).

CONCLUSIONS

Smoking is known to be a risk factor for AMD and this study suggests that smokers are at no more risk of developing neovascular than atrophic lesions.

Leading causes of certification for blindness and partial sight in England & Wales

Background

Prevention of visual impairment is an international priority agreed at the World Health Assembly of 2002- yet many countries lack contemporary data about incidence and causes from which priorities for prevention, treatment and management can be identified.

Methods

Registration as blind or partially-sighted in England and Wales is voluntary and is initiated by certification by a consultant ophthalmologist. From all certificates completed during the year April 1999 to March 2000, the main cause of visual loss was ascertained where possible and here we present information on the leading causes observed and comment on changes in the three leading causes since the last analysis conducted for 1990–1991 data.

Results

13788 people were certified as blind, 19107 were certified as partially sighted. The majority of certifications were in the older age groups. The most commonly recorded main cause of certifications for both blindness (57.2 %) and partial sight (56 %) was degeneration of the macula and posterior pole which largely comprises age-related macular degeneration. Glaucoma and diabetic retinopathy were the next most commonly recorded main causes. Overall, the age specific incidence of all three leading causes has increased since 1990–1991 – with changes in diabetic retinopathy being the most marked – particularly in the over 65's where figures have more than doubled.

Conclusion

The numbers of individuals per 100,000 population being certified blind or partially sighted due to the three leading causes – AMD, diabetic retinopathy and glaucoma have increased since 1990. This may to some extent be explained by improved ascertainment. The process of registration for severe visual impairment in England and Wales is currently undergoing review. Efforts must be made to ensure that routine collection of data on causes of severe visual impairment is continued, particularly in this age of improved technology, to allow such trends to be monitored and changes in policy to be informed.

Nitrite-induced cross-linking alters remodeling and mechanical properties of collagenous engineered tissues

Cumulative damage to long-lived connective tissue proteins play a key role in the development of age-related human diseases such as cardiovascular stiffening and age-related macular degeneration. The processes that result in the accumulation of increasingly insoluble, undigestible damaged collagen are only partially known. Nonenzymatic glycation (NEG) is one such process and has been linked to the development of diabetic-related complications and aging. An additional novel mechanism particularly relevant to smoking- and inflammation-related diseases involves the nonenzymatic nitrite (NEN) modification of connective tissue proteins. The present study was undertaken to examine the effects of NEN of fibrillar type I collagen on cell-mediated remodeling and mechanical properties of collagenous tissues. Using a modification of an in vitro fibroblast-populated collagen gel model system developed in our laboratory, we tested two hypotheses: NEN reduces the ability of primary adult cardiac fibroblasts to remodel type I collagen gels; NEN reduces the deformability of type I collagen gels subjected to mechanical testing. The results show that NEN impairs both cell-mediated remodeling and mechanical deformability in collagenous engineered tissues. Furthermore, these mechanical changes correlate with the degree of cross-linking as determined by SDS-PAGE. Thus, we concluded that NEN reactions may contribute to alterations in the biomechanical properties of collagen-containing tissues consistent with the age-related functional decline observed in human disease.